kotlin 协程 TCP demo

以下是基于 Kotlin 协程的 TCP Demo。它使用 Kotlin 协程中提供的 `Socket`、`ServerSocket` 等类来完成 TCP 通信。

1. 客户端：

import kotlinx.coroutines.Dispatchers
import kotlinx.coroutines.GlobalScope
import kotlinx.coroutines.launch
import kotlinx.coroutines.runBlocking
import java.io.BufferedReader
import java.io.InputStreamReader
import java.io.PrintWriter
import java.net.Socket

fun main() = runBlocking {
    val socket = Socket("localhost", 12345)
    val reader = BufferedReader(InputStreamReader(socket.getInputStream()))
    val writer = PrintWriter(socket.getOutputStream(), true)

    GlobalScope.launch(Dispatchers.IO) {
        while (true) {
            val line = reader.readLine()
            println("Server: $line")
        }
    }

    while (true) {
        val input = readLine() ?: break
        writer.println(input)
    }
}

2. 服务端：

import kotlinx.coroutines.Dispatchers
import kotlinx.coroutines.GlobalScope
import kotlinx.coroutines.launch
import kotlinx.coroutines.runBlocking
import java.io.BufferedReader
import java.io.InputStreamReader
import java.io.PrintWriter
import java.net.ServerSocket

fun main() = runBlocking {
    val serverSocket = ServerSocket(12345)

    while (true) {
        val socket = serverSocket.accept()
        val reader = BufferedReader(InputStreamReader(socket.getInputStream()))
        val writer = PrintWriter(socket.getOutputStream(), true)

        GlobalScope.launch(Dispatchers.IO) {
            while (true) {
                val line = reader.readLine()
                println("Client: $line")
                writer.println("You said: $line")
            }
        }
    }
}

在运行客户端和服务端之后，可以在客户端输入消息并发送到服务端，服务端会将消息回显给客户端。